Sheet detecting device



-May 18, 1954 K I 2,678,822

SHEET DETECTING DEVICE Filed May a, 1951 4 Sheets-Sheet 1 Ji/VEA/ 70 R M 8, 1954 H. T. BAcKHousE 2,673,822

SHEET DETECTING DEVICE Filed May 8, 1951 4 Sheets-Sheet 2 IAIVEAJTVZ @44 77M 8 BY 51 ATTIRI E V May 18. 1954 H. T. BACKHOUSE SHEET DETECTING DEVICE 4 Sheets-Sheet 3 Filed May 8. 1951 ATYaZA/EY! May 18, 1954 H. T. BACKHOUSE 2,678,822 SHEET DETECTING DEVICE Filed May 8, 195; I

4 Sheets-Sheet 4 A-rmz new Patented May 18, 1954 UNITED STATES iATENT OFF ICE SHEET DETECTING DEVICE Headley Townsend Backhouse, Sunningdale, England Application May 8, 1951, Serial No. 225,250

4 Claims.

The invention relates to sheet detecting devices of the kind employed in conjunction with sheet feeding machines, printing machines or other machines operating on individual sheets in, which the sheets are fed in succession over a feed-board or lay-board or front plate (herein generically termed a feed-board) to determine the non-arrival at the proper time in the cycle of operations of the machine of a sheet at a particular position on the feed-board and comprising a detfictor finger at that position arranged for engagement by the leading edge of a properly timed sheet and to be moved by such engagement, the arrangement being that if the finger is not so moved at the proper time, the operation of the machine is stopped or a warning device is operated. Detector fingers, arranged in this, way are commonly provided in conjunction with front lays or stops to detect the nonwarrival at the laws or at a position immediately before the lays, of a sheet at the proper time.

The invention provides a sheet detecting device of the kind described in which the detector finger extends upwardly, in which means arev provided for giving to the finger a reciprocatory movement from a position at which the upper end of the finger is below the plane of the surface of. the feed-board to a position at which the upper end is above the plane for engagement by the leading edge of a sheet advancing over the board, in which the detector finger is pivotally supported at its lower end on the means for effecting the reciprocatory movement, the pivotal connection permitting swinging movement of the upper end on engagement by a moving sheet, in which the finger has a downwardly directed abutment surface (e. g. a step on the finger) adjacent its upper end and in which there is a stop positioned to engage the abutment surface on downward movement of the finger thereby to arrest the movement of the finger unless the finger has been swung (i. e. carried forward) by a sheet as aforesaid so as to move the abutment clear of the stop, the. arrangement being that arrest of the finger as aforesaid stops, or may be employed to stop, the operation of a printing, feeding or other machine with which the detector is associated or to efiect the operation of a warning signal.

There may be several fingers and associated stops distributed across the direction of advance of the sheet and means may be provided whereby selected fingers may be rendered inoperative.

In the preferred form of the invention there is included spring means lightly urging the finger to swing into the position. in which the abutment surface will engage the stop.

The stop may be constituted by, or afilxed to, a part of the feed-board. Alternatively, when the invention is employed in conjunction with a front lay the stop may be constituted by, or aifixed to, a part of the lay and be arranged to move with the lay when the latter is taken out of the path of'the sheet after registration, to permit removal of the sheet. In each case the stop and finger are preferably adjustable in position in the direction of feeding of the sheets.

In one construction according to the invention the abutment surface is undercut (e. g. like a crochet hook) and the stop provides a sloping surface to mate with the undercut abutment.

Three specific constructions of detecting devices according to the invention as applied to rotary printing machines will now be described by way of example and with reference to the drawings, in which:

Figure 1 is a perspective view showing the first example with part of the feed-board cut away;

Figure 2 is a side view of the second example;

Figure 3 is a front view of the mechanism shown in Figure 2;

Figure 4 is a view similar to Figure 2 but showing the parts in different positions; and

Figures 5 and 6 are views showing the third example in difierent positions.

In each example, the printing machine is provided with a feed-board I from which the sheets are taken to the cylinder in the usual manner (e. g. by means of swinging grippers). The feedboard is provided with front and side lays against which accurate registration of the sheets is effected.

Further, in each example, there are at the front edge of the feed-board immediately behind the front lays two or more detector fingers 3 spaced apart across the board. In each example the fingers and their operating mechanisms, are similar in construction and arrangement, and only one will be described.

In the first example, shown in Figure 1, there are two fingers 3 and each finger extends upwardly through a slot or notch in the feed-board i At its lower end the finger 3 is attached to the free end of an arm 6 which extends from a crossshaft underneath the board, the arm extending rearwardly from the finger. A second arm 8 extends downwardly from the shaft 1 at the side of the board I. and has a follower 9 cooperating with a cam in on a rotatable shaft II below the feedboard and extending across the board. A springurged plunger [2; in the lever lightly urges the finger 3 to rotate about its pivotal connection in the direction to move the upper end of the finger 3 rearwardly (i. e. to meet the edge of a sheet advancing over the feed-board towards the front lays).

Adjacent the upper end of the finger 3 there is a step 53 on the rear face of the finger which provides a downwardly directed abutment surface. Above the step IS the rear face of the finger 3 is curved upwardly and rearwardly. The step 13 is slightly undercut.

Recessed into the surface of the feed-board I there is a stop-plate M which provides an upwardly directed surface l5 sloped to mate with the undercut step it on the finger 3. The stopplate It is adjustable in position in the direction of movement of the sheets by means of the eccentric l6 and is secured by means of the screws II.

In use the cam tends to rock the shaft 1 to move the upper end of the finger 3 from a position at which it lies below the surface of the feed-board l and the step it lies below the mating surface l5 of the stop-plate M, to a position in which the upper end of the finger 3 extends above the surface of the feed-board l and the abutment step is above the surface I5 of the stopplate it. The timing of the movements of the finger 3 is such that if a properly timed sheet is advancing over the feed-board 1 towards the front lays, the front edge of the sheet will engage the upper end of the finger 3 when it is above the feed-board and will swing the finger about its pivotal support to move the abutment step away from the stop-plate. When so moved the finger 3 clears the stop-plate in its downward movement. Should a sheet fail to arrive at the proper time the finger 3 will not be swung about its pivotal support and in its downward movement the abutment step I3 will make a latching engagement with the surface E5 of the stop plate M, as shown in the drawing, thereby preventing further downward movement of the finger 3. The effect of this is to stop the operation of the rock-shaft l which in turn stops the operation of the press by well-known means not shown in the drawings.

In the second example shown in Figures 2, 3 and 4-. there are four front lays 26] associated with four detector fingers 3 respectively. The lays 20 operate from below the feed board 1 and are carried on a transverse rock-shaft 2i beneath the board and behind the front edge thereof. Each lay 2!} is carried on the free end of an arm 22 on the rock-shaft 21 which arm, when the lay 2c is in the operative position, extends from the rock-shaft substantially parallel to the underside of the board I. The lay 20 is of L-shape, one limb, 23, lying along the top of the arm 22 and being adjustably secured thereto and the other limb extending upwardly through a notch in the board to provide on its rear upwardly extending face the lay-surface 24. A throughway 26 is formed in the upwardly extending limb for the reception of the detector finger 3 and the limb 23 provides a sloping stop surface 21 for engagement by a step 28 on the finger 3, the finger 3 being formed as in the previous example shown in Figure 1.

At its lower end the finger 3 is pivotally sup ported on the free end of an arm 29 which extends, approximately parallel to and underneath the arm 22 carrying the lay 20, from a second rock-shaft 39 which is below and parallel to the first shaft. The finger 3 is, as before, lightly spring-urged to engage the edge of a sheet approaching the front lays 20 and an adjustable stop 32 is provided limiting the extent of movement of the finger by the spring. This adjustment may be used to compensate for adjusting movements of the lay as about to be described. The adjustment may also be used to render inoperative any fingers not required for use.

The L-shaped lay is adjustable along the length of the arm 22 on which it is carried by means of an eccentric 34 on the arm engaging in a slot in the limb laying along the arm and accessible for rotation by a key or screw-driver through a slot 35 in the feed board i. A clamping screw 36 holds the lay in its adjusted position and the purpose of the adjustment is to enable a precise registration of the sheets in relation to the press cylinder to be achieved.

In the operation of this example (shown in Figures 2, 3 and 4) the rocleshaft 22 carrying the lays 2b, is rocked, by means of arm 31, to elevate the lay surfaces into the path of a sheet advancing over the feed-board l and the rock shaft 30 is rocked to elevate the upper end of the finger 3 above the board. Immediately after the time at which a sheet should have arrived at the front lays 2b the shaft 30 is rocked to lower the fingers 3, the motion being derived from a check shaft through arm 38. If a properly timed sheet has arrived it will have swung the fingers 3 and the steps on the fingers will in their downward movement clear the stops on the lays Ell. If a sheet has not arrived, the fingers 3 will engage the stop, their downward movement will be arrested and the operation of the machine will be stopped. If a sheet arrives askew then one of the fingers 2 will operate to stop the machine in this manner. After the fingers 3 have been lowered and cleared the stops, the front lays 20 are lowered to permit removal of the sheet.

In a modification of the example just described, the adjustment of the lays is effected by movement of the rock-shaft 2i beneath the board. The shaft may be moved bodily or either end may be moved. independently of the other, this arrangement having the advantage over that previously described that alignment of the lay surfaces is maintained. The adjustment may be efiected by supporting bearing blocks for the shaft in guideways and by providing adjustable eccentrics on the bearings operating against fixed frame parts to move the bearings along their guideways, return movement being effected by springs. The bearing blocks may also carry the rock-shaft 3i? for the fingers.

In the case of a machine which is to be used with sheets of substantially different widths, it is possible to employ two detector fingers as described above and to arrange for the fingers to be adjustable across the width of the board to suit the different sizes of sheets. It is, however, preferred to provide a series of fingers at fixed positions across the board and to arrange that only those fingers positioned to suit the sheets being used may be selected for operation. Usually the two fingers positioned to engage the front edge of the sheets nearest to the sides thereof will be used. Figures 5 and 6 show one form of detector finger embodying means by wh ch it may readily be brought into use or, for the above purpose, rendered inoperative. The detector finger 3 is pivotally supported, as in the first example, from an arm 49 and is lightly urged in the clockwise direction by a spring leaf 4!. The finger 3 eo-operates with a stop-plate 42. A plate 43 is secured below the arm 40 by :bolts 44 received within slots 45 in the plate which permit a limited degree of lengthwise sliding adjustment of the plate. Spring washers 46 provide a frictional grip tending to hold the plate 43 in its position of adjustment. Screwed into the plate 53 is a headed pin 31 which projects above the plate 43. When the plate is moved to the right up to the limit of its adjustment as shown in Figure 5, the projecting portion of the pin 4? lies clear of the tail 48 of the finger 3 and the finger is operative. If the plate is moved to the left as shown in Figure 6 the pin 41 engages under the tail 48 of the ringer 3 and thereby holds the finger clear of the stop plate 42 and inoperative.

The invention is not restricted to the application to printing machines as just described. It may for instance be applied to a sheet separating and feeding machine, for example of the kind which separates the sheets one at a time from the top of the pile and transfers them to a feed conveyor which carries them to a feed-board where registration of the sheets is effected.

I claim:

1. In a machine for operating on a succession of individual sheets and having a feed-board over which the sheets are fed in succession, a sheet detecting device for determining the non-arrival at the proper time in the cycle of operations of the machine of a sheet at a particular position on the feed-board and comprising a detector finger at that position extending upwardly, means for giving to the finger a reciprocatory movement from a position at which the upper end of the finger is below the plane of the surface of the feed-board to a position at which the upper end is above the plane for engagement by the leading edge of a sheet advancing over the feedboard, the finger being pivotally supported about a horizontal transverse axis at its lower end on the means for effecting the reciprocatory movement thereby to permit forward swinging movement of the upper end on engagement by a moving sheet, and the fingeralso having at its rear side a downwardly directed abutment surface near its upper end, and a stop positioned to engage the abutment surface on downward movement of the finger thereby to arrest the movement of the finger unless the finger has been swung forwardly by a sheet as aforesaid so as to move the abutment clear of the stop, the arrangement being that arrest of the finger as aforesaid may be employed to stop the machine.

2. In a machine for operating on a succession of individual sheets and having a feed-board over which the sheets are fed in succession, a sheet detecting device as claimed in claim 9 in which there are several fingers and associated stops as aforesaid distributed across the direction of advance of the sheets and in which means are provided whereby selected fingers may be rendered inoperative.

3. A sheet detecting device as claimed in claim 1 in which the stop is adjustably secured in position.

A sheet detecting device as claimed in claim 1 in which the abutment surface of the finger is undercut and the stop provides a sloping surface to mate with the undercut abutment.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,741,848 Kelly Dec. 31, 1929 1,883,471 Barrett Oct. 18, 1932 2,499,125 Backhouse Feb. 28, 1950 2,579,406 Tebbs Dec. 18, 1951 FOREIGN PATENTS Number Country Date 580,346 Great Britain Sept. 4, 1946 

